Dual licensing -- other wrinkles

[John Cowan]

No Spam scripsit:

> 1. Can I simply write a preamble in my headers saying "if you didn't
> pay for this, it is licensed under GPL; if you did pay for this,
> you can either choose GPL or (unnamed commercial license)"?

Sure.

> 2. I'm not interested in the complexities of collecting sublicensing
> and subsublicensing fees -- all I want to do is, if you pay for it,
> you can use it any way you see fit, including except that you can't
> sublicense it as anything else but GPL. Would the header preamble
> handle this? Is it sufficient for the other license to be some sort
> of permissive non-reciprocal license like CPL, BSD, etc., or do I have
> to put more teeth into it?

I'm not sure what the point is of doing a dual license like that.
You normally dual license either to be compatible with two different
codebases (both GPL and MPL, say) or to let people pay to opt out from
reciprocity.

> 3. Suppose at some later stage, I discover another GPL'ed derivative
> of my work in the wild. Does the fact that I have dual license mean
> that if the other author says, "I don't want to submit this code back
> to you under your dual license", I cannot then incorporate his code
> back into my dual licensed code base?

The GPL doesn't force people to publish their changes in any way, except
that if they publish modified binaries, they must publish modified
sources at no additional charge (to prevent holding up the sources
for ransom).  If you get changes licensed under the GPL, you can't
incorporate them into the commercially licensed version of your app
unless the author either transfers copyright to you or gives you a
license to do so -- and you can't extort consent in advance, either.

-- 
John Cowan  www.ccil.org/~cowan  www.reutershealth.com  jcowan at reutershealth.com
SAXParserFactory [is] a hideous, evil monstrosity of a class that should
be hung, shot, beheaded, drawn and quartered, burned at the stake,
buried in unconsecrated ground, dug up, cremated, and the ashes tossed
in the Tiber while the complete cast of Wicked sings "Ding dong, the
witch is dead."  --Elliotte Rusty Harold on xml-dev
--
license-discuss archive is at http://crynwr.com/cgi-bin/ezmlm-cgi?3